Heat transfer bridge

ABSTRACT

A heat transfer bridge for absorbing heat from electronic circuits and electrical distribution transformers to thereby cool said components is disclosed. The heat transfer bridge includes a passive pump for pumping a fluid having a low boiling point that readily creates bubbles when heated to its boiling point. The bubbles are directed via selected flow paths to effectively push or drive the fluid from adjacent a heat source such as an electronic circuit or transformer to heat dissipating components such as cooling fins. In one embodiment, the fluid in the inventive heat transfer bridge comprises a fluid comprising metallic slurry that provides many times the heat dissipation rate as compared to a clear fluid.

BACKGROUND OF THE INVENTION

This utility application claims the benefit of the earlier filing date of the provisional application of the same title, “Heat Transfer Bridge”, Ser. No. 61/575,946 having a filing date of Aug. 31, 2011 and of the same inventor, Troy W. Livingston.

The present invention relates to system for removing heat from heat generating components, and more particularly to a method and system for removing heat from electronic circuit boards, electronic chips and transformers.

As is well known in the electrical industry, circuit boards and electronic chips and transformers create unwanted heat during operation. Heat build-up may cause a circuit board or transformer to malfunction or burn up and cause the entire system to also malfunction or to short out. The problem has become even more acute due to the fact that circuit boards have become smaller and/or more highly populated with components thus causing the source of heat to become more intense. Accordingly, the heat build-up in circuit boards and IC chips must be dissipated. In the case of transformers often many additional houses are built and connected to be serviced by transformers already operating at rated load and the additional loading heavy loads causes high heat resulting in damage and shorting of the transformer windings. Heat build-up in pole mounted power transformers is a primary cause of transformer failures.

There are many existing method of heat dissipation from electronic circuit boards, IC chips and electronic systems. These include providing layers of exotic metals, forced gas and liquid cooling, heat convection, pulsating heat pipes, coolant baths and heat transfer directly to the system housing. Liquid cooling systems mentioned above, which are generally the most effective, require a pump to move a coolant from the heat source to a remote heat sink where the heat is dissipated. These latter systems are voluminous and heavy.

There is a need for providing a method and system for developing a circuit board and IC chip cooling system which will enable designers and engineers to create and operate electronic systems that are smaller in size and lighter in weight. It is thus an object and purpose of the present invention to address the foregoing problem and to provide a system and method for efficiently removing heat from circuit boards and IC chips which system is itself small and of light weight.

There is also a need for increasing the output of power line transformers without having to replace the transformers, and accordingly to provide improved cooling of the transformer during operation which will result in an increased capability of operating the transformers at a higher rating and/or to reduce the heat stress on the transformers.

SUMMARY OF THE INVENTION

A basic feature of the present invention is the utilization of a system and structure including a passive transfer pump for cycling a liquid having or carrying a metallic slurry in the liquid. The pump is driven by the heat source itself. More specifically, the present invention rapidly removes thermal energy from a heat source to heat sink areas by incorporating a bubble generating effect of the low boiling point of a fluid to pump the liquid in a closed loop to the heat dissipating areas. The inventive system has no moving parts and therefore eliminates the maintenance and service life restrictions found in rotating or pulsating pump systems. An important feature of the invention is that it provides an efficient means of removing heat from a source wherein the liquid carries a metallic slurry that has been found to be multiple times more effective in transferring and conveying heat from one surface to another than does a liquid such as a fluorocarbon as water.

In one embodiment, the present invention provides a heat transfer bridge or dissipation module for electronic circuit boards and IC chips utilizing a passive pump cycling the cooling liquid. The liquid may include a slurry of metallic particles which enhances the transfer of heat. The invention can be utilized with a few or a large array of circuit boards as well as for circuit boards and IC chips mounted in a tight circuit configuration. Further, the heat dissipation system or module is small and can be mounted in practically any orientation.

In a second embodiment, the present invention provides a heat transfer bridge for power transformers that can be non evasively retrofitted onto transformers and can be included in building new transformers. Transformers as referred to herein comprise a primary winding and a secondary winding which must be physically and electrically separated from one another. Electrical separation is achieved by use of an insulating material. The dielectric strength of an insulating material is reduced with increasing temperature. Continuous transformer operation at elevated temperatures therefore results in faster aging of the insulating material with a consequent reduction of the insulating properties of the material. Reduction or loss of the insulating properties of the material results in the failure of the transformer.

Importantly, it has been found that the inventive heat transfer bridge or module which provides a unique system utilizing a passive heat pump to circulate a liquid slurry carrying metallic particle may be utilized in both the first embodiment of the invention for cooling electronic components and in a second embodiment for cooling power line transformers.

The foregoing features and advantages of the present invention will be apparent from the following more particular description of the invention. The accompanying drawings, listed herein below, are useful in explaining the invention.

DRAWINGS

FIG. 1 is a view in cross section of a structure useful in explaining the concept of the inventive heat transfer pump;

FIG. 2 is a side view in of a second embodiment of the heat transfer pump;

FIG. 3 is a cross section view of the embodiment of FIG. 2.

FIG. 4 show the embodiment of FIG. 2 mounted in a horizontal orientation

FIG. 5 is an isometric view of an array of the inventive heat transfer pumps;

FIG. 6 is a side view showing the heat sink comprises a bracket mounted to the wall of an electronic cabinet;

FIG. 7 is a side showing the heat sink mounted directly to an electronic cabinet;

FIG. 8 is a side view showing a section of the fluid flow path that is inclined from the horizontal;

FIG. 9 is a side view to show an assembly wherein an additional flow channel is provided such that regardless of the mounting position the fluid path will not be blocked;

FIG. 10 shows the overall heat transfer pump assembly is mounted at an acute angle;

FIG. 11 is view of the bubble carrying tube 14 is mounted at an acute angle and wherein a single tube provides both the upward and downward flow paths;

FIG. 12 is an end view of the tube of FIG. 11 to more clearly show the heat sink fins of the structure of FIG. 11;

FIG. 13 is a view to show a tube having a center divider to provide a separate return flow path for the cooled fluid;

FIG. 14 is a side view of the pump is mounted to a manifold heat sink;

FIG. 15 is an isometric view of the manifold heat sink of FIG. 14;

FIG. 16 is a view essentially similar to FIG. 1 wherein the pump is mounted onto a heat sink to cool a circuit board;

FIG. 17 is a top view of FIG. 16 showing the cooling fins of the heat sink of FIG. 16;

FIG. 18 is a view to depicting the pump operating in the manifold environment of FIG. 16;

FIG. 19 is a view to show the fluid flow path a heat source comprising a circuit board;

FIGS. 20A, 20B and 20C depict the fluid conveying action of a bubble;

FIG. 21 depicts the cat whiskers developed in the electrolysis plating of copper plating;

FIG. 22 depicts the mounting of a circuit board on a cabinet bracket;

FIG. 23 is a view of the pump assembly mounted on a circuit board;

FIG. 24 is a view to show the thermal gel used to make good thermal contact between two metal surfaces;

FIG. 25 is an isometric view of the passive heat transfer pump mounted to a frame of an electronic cabinet; FIG. 26 is a section view of an embodiment of a

FIG. 26 is a section view of an embodiment of a heat pump having a rotating screw mounted in the pump tube to provide a vortex action to the fluid flow;

FIG. 27 is a section view of a heat transfer module showing the chamber where bubbles are generated and the associated pump tubes;

FIG. 28 shows a heat transfer module and multiple slurry flow paths extending through the cooling fins;

FIG. 29 shows the action of the bubbles and the slurry pumping paths;

FIG. 30 shows a variation of the pumping tube and return path of the liquid slurry;

FIG. 31 is relatively hugely enlarged view depicting the action of the metal particles carried in the slurry as the particles strike the heat input plate;

FIG. 32A is an expanded view depicting the insertion of a fine coil spring in the heat dissipating tube;

FIG. 32B depicts the turbulent action provided by the coil spring of FIG. 32A;

FIG. 33 depicts an oil filled type of power distribution transformer indicating in dotted lines the mounting of an inventive heat dissipating module to the side of the transformer;

FIG. 34 shows an inventive cooling collar for mounting the heat dissipating module on the transformer of FIG. 33;

FIG. 35 is a cross section view of the collar of FIG. 34 to show the slurry flow paths for cooling the transformer;

FIG. 36 shows an oil filled power transformer having two external oil cooling tubes;

FIG. 37 is a cross section view of the transformer of FIG. 36 to show the slurry flow paths through the two cooling tubes;

FIG. 38 is an isometric view to show a modification of the cooling structure depicted in FIGS. 34 and 36 wherein the path for the inventive cooling slurry is directed through a pump embedded in the transformer laminations; and

FIG. 39 is a cross section view of the heat dissipating module of FIG. 38 showing the inclusion of the turbulence spring in the return path for the slurry.

DESCRIPTION OF THE INVENTION

As alluded to above, one of the problems for developing circuit boards and IC chips, is the need for dissipating the heat generated by the components which operate at higher output/wattage. Further a problem for dissipating heat from circuit boards and IC chips is that the boards and chips are mounted in various orientations and in environments which may restrict air flow. The restricted and oft times minimal air flow will reduce the cooling capacity of hot surface and heat sinks/dissipating structure. The electronic junctions used in circuit boards are very small, therefore to be effective as a heat dissipation module, a module heat must efficiently absorb and dissipate heat energy from this small area.

It has been found that liquid cooling for circuit boards and IC chips is one of the most effective ways of cooling these components. It is standard practice to utilize pumps and compressors and refrigeration cycles to provide the liquid flow in a closed loop to carry the heat energy from the heat source to a heat sink to dissipate the heat. While the foregoing structure may be useful, it is large, cumbersome and generally cannot be mounted to small circuit boards and IC chips such as used in present day computers and other electronic devices.

Accordingly, the present invention is directed to providing a method and system for utilizing liquid cooling of electronic circuits and IC chip utilizing a means of circulating the cooling liquid utilizing a passive heat transfer pump. The passive heat pump of the invention utilizes the heat energy of the components themselves to circulate the fluid. In researching the matter, the inventor herein found that the properties of dichloromethane (methylene chloride) would enable the development of the subject heat transfer pump. Dichloromethane is volatile and has a low boiling point. When the fluid is contained an essentially vertically oriented tube and heat is applied to the lowered end of the tube, the fluid will boil at one hundred three (103) degrees Fahrenheit. As the fluid is heated above its boiling point, bubbles of methylene chloride will form and rise to the top of the tube. As the bubbles rise the hot fluid above the bubbles will be pushed up by the bubbles. As the bubbles continue to be formed, more and more hot fluid will be pushed upwardly. The fluid it carries the heat energy from the heat applied to the tube. This action will continue as heat is present and more bubbles are formed. The distance between the bottom of the fluid to the top is great enough so that fluid at the top of the tube stays remains substantially below its boiling point. The fluid cools down. Thus, as the bubbles get near the top of the tube, the bubbles break up and condense, and the fluid is no longer pushed up by the bubbles and returns back down the tube. The inventive concept utilizes the foregoing principle and incorporates one or more heat sinks in the flow path of the hot fluid and provides fluid return paths forming closed loops to extract heat from the moving fluid. The bubbles thus provide the pushing or pumping force to drive the hot fluid in a closed loop and heat sinks are provided adjacent the fluid flow path to extract heat from the fluid.

In one basic embodiment of the invention, dichloromethane is used as the fluid due to its low boiling point. As will be explained more fully herein below, the bubbles developed by a circuit board or IC chip is utilized to pump the fluid dichloromethane (methylene chloride) up an enclosed tube to move the hot fluid up the tube through a first channel to a position adjacent a heat sink where the fluid cools. The cooled fluid is returned through a separate channel and connecting the top and bottom of the tube, and the cycle repeats. Thus, the present invention provides a passive heat transfer pump. Other fluids that have a low boiling point could likewise be used; however, methylene chloride is readily available, effective and inexpensive.

Referring to FIG. 1, for a more detailed explanation of the inventive concept, that is, the formation and action of the bubbles. Heat transfer pump 11 includes an outer housing tube 12. A closed concentric inner tube 14 is mounted within housing 12. A bubble guide tube 18 is mounted within tube 14 and volumetric sections above and below the closed ends of tube 14. The lower end of bubble guide tube 18 forms a wide mouth funnel.

A methylene chloride fluid which is the least toxic of the simple hydrocarbons, indicated at 31, is contained in the tube 14. Methylene chloride or dichloromethane is a volatile fluid which has a low boiling point of 39.6 degrees C. (103 degrees F.). This fluid low boiling point is utilized to transfer heat energy from the hot heat sources to external heat sinks or heat dissipating components.

Assuming a heat source is applied at the lower end 26 of tube 14 which is formed as a funnel. When the dichloromethane 31 adjacent end 26 reaches its boiling point of 39.6 degrees C. the fluid will start to produce bubbles 10 and the bubbles will rise and move (push) upwardly through the open funnel end of tube 18. The spaced bubbles 10 formed by the fluid boiling action are approximately 4 mm in diameter. Bubble guide tube 18 through which the bubbles move also has an internal diameter also of 4 mm. As the fluid 31 continues to boil, more bubbles 10 with a finite spacing between them are formed adjacent to the heat source and rise up the tube 18. A hot fluid 31 is confined (entrapped) in the spacing between the bubbles. It has been found that the bubbles 10 pushes (carry) the hot fluid 31 confined between the bubbles upwardly via flow path 17. The rising bubbles 10 thus provide a positive pumping, pushing and driving action to move the hot fluid 31. The hot methylene chloride fluid 31 is thus pumped up tube 18 by the rising bubbles 10 and as the fluid 31 flows past heat sinks (concentrators) 24 mounted adjacent to the top of housing 12, heat energy is absorbed and conveyed to fins or other external heat dissipating components. A required fluid expansion volume 19 is provided adjacent to the top of tube 14. The now cooled fluid 31 and exits at the top of the tube 18 and the cool fluid returns down paths 23 and 25 to the bottom of tube 14. The cooled fluid 30 is again next heated and the cycle is repeated. The apparatus of FIG. 1 thus comprises a heat transfer assembly powered by a passive heat pump.

To address the problem of varying physical orientations of circuit boards and IC chip and internal positioning of the heat generating sources therein another embodiment 11A of the pump is disclosed herein. Referring to FIG. 2, the pump 11A is configured as a figure eight pattern comprising a rectangular outside housing wall 32, an enclosed inside wall 34 formed within wall 32, and a pair of rectangular fluid guide walls 36 and 38 formed adjacent wall 34 and positioned to form a FIG. 8 shaped channel 39 within wall 34. Two thickened sections 35 and 40 are formed on the surface of outside wall 32 on the upper left and lower left (as oriented in FIGS. 2 and 3) that function as heat concentrators. A heat source is provided to heat to heat concentrator 40 is mounted on the left bottom wall 32. Fluid flows through the paths indicated by figure eight pattern by numeral 39, 14, 42,14A and 45.

In operation, with the pump 11A mounted in a vertical orientation as shown in FIGS. 2 and 3, the flow paths of the liquid 31 and bubbles 10 is indicated by the cross hatching and arrow lines 44 and 46 in FIG. 3. The required fluid expansion region (void) is indicated by numeral 47 in FIG. 3.

When pump 11A is mounted in a horizontal orientation as depicted in FIG. 4, a heat source is applied to heat concentrator 37, and the bubbles 10 developed in channel region 50 will have a flow path extending upwardly through flow path 42, (the bight or center of the figure eight configuration). the bubbles 10 generated by the heat energy will move or flow upward through flow path 42 and pump the fluid up path 42 and the bubbles 10 will condense and break down as the fluid cools. The fluid 31 pushed up path 42 will divide at the junction 49 and move through flow paths indicated by the arrow lines 43 and 45 and return to complete the cycle or loop at channel region 50. The heat concentrators 35 and 40 will remove heat energy from the flowing fluid 31.

As depicted in FIG. 5, the heat transfer pumps 11A can be conveniently combined or stacked as an array 62 of multiple modules to increase the cooling capacity of an assembly. The shape of the individual heat transfer pumps 11A may be flat as shown in FIG. 5, but the shape of said individual pumps may of other shapes adapted to the configuration circuit board or IC chip which the array 62 is intended to cool.

Refer now to FIGS. 6 and 7 which depict the mounting of a heat transfer pump 11B which is generally similar in structure function to heat transfer pump 11 of FIG. 1. Heat transfer pump 11B includes an outer elongated housing 63 and a fluid containing tube 64 mounted within said housing. Housing 63 is mounted to abut and cool an electronic circuit board 65. A tubular channel 66 extends through housing 63 and connects to the interior of tube 64 at the top of the tube. A second channel 67 connects to channel 66 and is formed within a bracket 69 which bracket in turn is affixed connected to a heat sink 70 and is mounted on an electronic cabinet 71. Another channel 68 extends through housing and connects to the interior tube 64 at the bottom of the tube. The channels 66, 67 and 68 thus form a closed loop flow path for the fluid 31. In operation, the circuit board 65 becomes heated thus creating the bubbles as described above, and the hot fluid is pushed up tube 64, as indicated by the arrow lines. The fluid 64 is pushed out through channel 66 to channel 67 where the hot fluid gives up heat energy to the bracket 69 and heat sink 70 comprising one or more fins. The now cooled fluid 31 flows downward to channel 68 to the bottom of tube 64. The fluid is then again heated and the cycle is repeated.

FIG. 7 is generally similar to FIG. 6 and functions in the same way. FIG. 7 depicts that a heat sink 70 may be the mounting bracket 69 itself and which is affixed by suitable screws to the electronic cabinet 71.

FIGS. 8 and 9 depict that a transfer pump 11C, similar in structure and function to heat transfer pump 11B of FIGS. 6 and 7, can be of different forms wherein the lower end of pump 11C is essentially embedded in a heat source. Also the channels 75, 76 and 77 which form the fluid flow paths are mounted at an angle to adapt to the circuit boards and IC chips which are to be cooled. FIG. 8 indicates that the fluid level rises as the fluid is heated.

FIG. 9 also depict an assembly wherein an additional fluid flow channel 78 is provided to connect to the other channels to the top of tube 14. The purpose of channel 78 to assure that when the transfer pump 11C is mounted in a tilted position, that the liquid level will be above an outlet from tube 14 to continue the fluid flow.

FIG. 10 relates to FIGS. 8 and 9. FIG. 10 is somewhat similar to FIGS. 6 and 7 showing that if the heat transfer pump 11C is be mounted at approximately at a forty-five degree angle, the fluid 31 will be at a level 81 above the outlet 82 and a vapor lock will occur. Accordingly, FIG. 10 shows why the provision of separate channel 78 as in FIG. 9 assures there is an expansion volume above the liquid level 81 in the tube so that the pump 11C may be mounted at an angle.

FIG. 11 shows a tube 11D, similar in function to tube 11 of FIG. 1, mounted at an angle a few degrees from the horizontal. It has been found that, a tube such as 11D will function to provide a cooling effect even though there is no bubble guide tube as in FIG. 1. Further, tests have shown that a tube 11 can be mounted at any angle greater than 5 (five) degrees from the horizontal and the tube will still function as a heat transfer pump. In FIG. 11, the pump 11D is mounted on an electronic circuit board 65. Heat from the circuit board 65 heats the fluid at the lower side (left) of tube 14, and bubbles 10 are formed that push the hot fluid from the lower left side toward the other or upper end of the tube. As the hot liquid releases its heat energy to the heat sink fins 80, the bubbles condense and break up, and the cooled liquid returns to the lower left of the tube 14. The cycle is repeated. This loop or circular flow of the fluid will occur in a single tube.

FIG. 11 is an end view of the transfer pump 11D of FIG. 10 intended to more clearly show the heat sink fins 80.

FIG. 13 shows a modification of the transfer pump 11D. Pump 11E shown in FIG. 12 includes a center divider 90A to provide a separate more distinct return channel for the cooled fluid 31, as depicted by the arrow lines.

FIG. 14 show a heat transfer pump 11F similar to tube 11B shown in FIGS. 6 and 7. In FIG. 14, the operation and function of tube 11F is essentially identical to the operation and function of tube 11F. In the structure of tube 11F the liquid outlet channel 66 from tube 14 extends through the side of the electronic cabinet 71 wall. A manifold heat sink 83 comprised of a series of perpendicular pipes connected in parallel from outlet channel 66 to return channel 68 provide respective fluid flow paths channel 66 to channel 68. Fluid flow is thus provided through multiple paths in the heat sink 83 to effectively cool the hot liquid 31. FIG. 15 is an isometric view to more clearly show the structure of the manifold 83.

FIG. 16 is a view of a transfer heat pump 11G similar in function and operation to heat transfer pump 11 wherein a bubble guide tube 18 mounted concentrically with fluid containing tube 14 to provide an upward flow path and a return path to circulate the fluid 31. The heat transfer pump is mounted directly onto a circuit board 65. Refer now also to FIG. 17 that show that a group of fins 85 are mounted along the elongated length of housing 14 and around the housing to provide a heat sink and heat dissipating area.

FIG. 18 shows another method of mounting a heat transfer pump 11H onto a circuit board 65. The function and operation of heat pump 11H are similar to pump 11B of FIGS. 6 and 7. In transfer pump 11H, the circuit board and the associated bracket 65A form a section of the bubble guide tube 64 and is mounted adjacent the lower end of the tube. In this embodiment the circuit board 65A which is the heat generator is bathed by the fluid 31. The heat energy is transferred directly from the circuit board 65A to the fluid 31.

FIG. 19 is a view in cross section to show fluid flow paths for a fluid pump 11J that is generally similar in concept to pump 11H of FIG. 18. In FIG. 19, similarly to FIG. 18 the circuit board 65B to be cooled is mounted in the flow path of fluid 31. Two guide tubes 84 and 85 separated by divider 86 for the bubbles 10. The lower section of fluid containing tube 87 is relatively enlarged to accommodate a relatively larger volume of fluid to provide a higher heat dissipating feature. Again as in FIG. 18, the circuit board 65B is bathed by the fluid 31 and heat energy is directly transferred from the circuit board to the fluid 31. The bubbles 10 rise through the respective guide tubes 84 and 85 and the hot fluid being pumped up by the bubbles flows out to respective heat sink manifolds 90 and 91 which manifolds may be generally similar to the manifold of FIG. 14. As is obvious, this embodiment of the heat transfer pump provides cooling for a heat source that generates a relatively large amount of heat.

FIGS. 20 (A, B, C) are useful in explaining the function of the bubbles in the bubble guide tubes, such as tube 18 in FIG. 1. It has been found that size of the bubbles formed by a given fluid under a given pressure and a given heat average can be determined by measurement. Dichloromethane bubbles at the boiling point expand to a diameter of about 4 mm. Referring first to FIG. 20B, since the bubbles will expand to an average of 4 mm, the bubble guide tube 18 is also formed to have a diameter of 4 mm. The spacing between the bubbles 10 is determined by the degrees of heat generated by the heat source, and amount of fluid 31 confined between the bubbles is thus determined by the heat of the source. Since the bubbles 10 are of the same diameter as the tube, the bubbles 10 will form a solid surface seal to push the fluid 31 upwardly and provide maximum efficiency in the pumping action.

Referring now to FIG. 20A, if the diameter of the bubbles 10 is larger than the diameter of the bubble guide tube 18, the bubbles 10 will be flattened or elongated and may not flow as freely through the guide tube, and the amount of fluid 31 between the bubbles may be reduced.

Referring now to FIG. 20C, if the bubble guide tube 18 is of a larger diameter than the diameter of the bubbles 10, the bubbles will not push the fluid 31 upwardly as efficiently as in FIG. 20B, i.e., some of the fluid 31 will slide and tend to rotate around the bubbles 10 as indicated by the arrow lines 31A. However, the rotating fluid 31A will create a turbulence which tends to add to the cooling effect of the fluid. This effect may be found in the pumps 11D in FIG. 11D, 11E in FIG. 13, and 11F of FIG. 14.

Refer now to FIGS. 21 and 22. It is known that in the electro deposition of copper whisker growth will occur and normally this phenomena of whisker growth is an undesired result. However in the present invention, electro deposits are made to purposefully enhance whisker growth, since it has been found that whiskers will provide a sharp point from which the formation of the bubbles 10 can be initiated. Accordingly, a copper layer 92 is electro deposited on one or more surfaces 94 connecting to the circuit board 65 purposefully causing whiskers 93 to be formed on layer 92. Whisker 93 provide sharp points that function as the initiating points for formation of the bubbles. FIG. 22 depicts the circuit board 65 mounted on an electronic cabinet.

FIG. 23 depicts a flat surface an electronic board 65 mounted to a flat surface of the inventive heat transfer pump 11. FIG. 24 is an enlarged view of the circled section of FIG. 23. As is known, and as depicted in FIG. 23 even smooth flat surfaces have micro undulation and in order to efficiently transfer heat between the heat source and the pump 11 a thermally conductive gel 96 is spread between the two surfaces as they are joined.

FIG. 25 is an isometric view to more clearly show one of the ways of mounting of the inventive heat transfer pump 11 on a bracket 97 of an electronic cabinet. Pump 11 is suitably sealed and positioned on a circuit board 65, not shown, powered by the leads 72. Circuit board 65 generates the heat to be cooled. The operation and structure of pump 11 have been described above. Bracket 97 comprises a cooling fin radiator of any suitable known type.

Refer now to FIG. 26. Scientific tables indicate that the transfer of heat using metallic material increases the thermal conductivity by a tremendous amount. Thermal conductivity of water at 20 degrees C. is given as 0.06 W/mK and that of copper at 385 W/mK. As a basic concept of the present invention described herein, it has been found that utilizing a heated fluid comprising a fluid/metal slurry 99 for forming bubbles and conveying and transferring heat from the heat source to cooling plates and fins greatly increases effectiveness of the fluid to reduce heat generated in electronic boards and transformers.

FIG. 26 shows the uses of a bubble pump 105 installed in a container 107 holding or containing a fluid metal slurry 99. In the embodiment described, the slurry 99 can be formed of copper particles. Any particles or micro balls of metal that are used have an almost balanced flotation coefficient wherein the particles will almost float on the fluid. Slurry 99 can also be formed as metallic balls or metal foams, as is known in the art to have a balanced flotation coefficient. Slurry 99 thus provides and efficient metallic slurry useful to transfer heat. The embodiment of FIG. 26 shows container 107 for a fluid metal slurry and a heat source comprising a printed circuit board 110 that develops heat in a bubble chamber 106 that generates initial bubbles 106A that coalesce to form larger bubbles 106 that are driven upwardly through bubble pump tube 105, all as previously described.

An axially extending screw 115 is positioned in tube 105, and has it lower end affixed to a horizontal plate 12 that in turned is rotatably supported on a pivot pin 121. The upper end of screw 105 is positioned against a pivot point 123. Screw 105 is freely rotatable. In operation, and as previously described, the fluid in chamber 106 is heated and bubbles 116A are formed that in turn coalesce into bubbles 116 and fluid is driven up pump tube 105. The moving slurry 99 rotates the screw and creates a vortex action that, as is known, enhances fluid flow. The slurry 99 and the included bubbles 116 exit the top of tube pump 105. The bubble 116 burst on reaching the fluid level 114. A fluid return tube 125 which has its opening at approximately the same level as the opening of pump tube 105 returns fluid 99 to bubble chamber 106 as indicated by the arrows 118 to thus complete the flow loop.

Refer now to FIGS. 27, 28 and 29 for a detailed showing and variations of the structure shown in FIG. 26. FIG. 27 depicts a heat transfer module 100 in accordance with the invention and including a heat source 110, a heat dissipating fin 112. FIG. 27 module having a number of pump tubes 105 positioned in the bubble chamber 106. As can be appreciated, each of the pump tubes 105 provides a circulating flow path 118 for the slurry 99. The slurry 99 transfers heat to the container 107A that turn transfer heat to the heat dissipating fin 112.

Refer now also to FIG. 28 that shows a module 100A generally similar to module 100 of FIG. 27, but wherein a manifold 120 is provided as return flow paths of for the slurry 99. FIG. 28 show a module having tube 123 upwardly to accommodate an expansion chamber which is higher than the flow path 117 for slurry 99. Flow path 117 extends horizontally to contact heat dissipating fin 112. Flow path 117 next tri-furcates into a manifold 120 as indicated by the arrows 114 to provide a larger volume of slurry 99 to be effective on heat dissipating fin 12. The return loop for the slurry is completed through return tube 119.

FIG. 29 is provided to show the interaction of the bubbles 116 and the metallic particles indicated as 99A, as well as the desired agitation and multiple return paths 118 developed in the bubble chamber 106.

FIG. 30 depict a heat transfer module 100B having the pump tube 105A oriented at an angle of about 35 degrees from the horizontal. The orientation of the pump tube 105A makes for an efficient operation. While the exact theory has not been developed, it appears that the bubbles 116 and fluid move more easily at this inclined angle. Otherwise, the operation of pump tube 105A similar to that of previously described pump tubes.

FIG. 31 will be described with reference to FIGS. 28 and 29. FIG. 31 shows the metallic foam or metallic ball micro particles 128 in slurry 99, in a vastly enlarged configuration; in one embodiment the particles 99 are in the 100-400 micro millimeter size range. As stated above, a basic concept of the invention is to provide metal foam particles or metallic micro balls in the slurry 99 which thus provides a much enhanced heat transfer capability to the fluid. FIG. 31 provides a concept and theory of the function and action of the metallic particles on the heat input plate 118. As depicted in FIG. 29 by the arrow line 114B the particles 126 combined from sub-particles 128, strikes the plate 118 of the bubble chamber 106 as indicated by the arrow line 130, as a glancing motion. The particle 126 then bounces up as indicated by the arrow line 130, or the particle slides on plate 118 as indicated by the arrow 132, or the particle rolls as indicted by the arrow line 134. In each of the foregoing actions the particle 126 is in contact with the heat input plate causing an efficient heat transfer there between.

Refer also to FIG. 32A that depicts a turbulence spring 172 in a heat dissipating tube 173 positioned in contact with heat dissipating fin in the return flow path 119 for the slurry 99. It has been found that to maintain good heat transferring contact of the metallic slurry with the tube 173 and thence to fin 112, it is desirable to maintain a turbulent flow of the slurry through the tubes in the flow return path. FIG. 32A depicts the insertion of a turbulence generating coil spring 172 inside the tube 173. FIG. 32 B depicts the flow of the slurry 99 through the tube 173. As the slurry flows past each coil of the spring, the flow will be disturbed to provide as turbulent flow as indicated by the arrows 99A. This causes a continual contact and better heat transfer between the metallic slurry and the sides of the tube 173. As shown in FIG. 30, the tube 173 is in metal to metal contact with heat dissipating fin 112, and thus an efficient heat transfer is effected between slurry 99 and fin 112.

FIG. 33 shows a pole mounted filled distribution transformer 131 in universal use and of well known construction. The transformer 131 comprises a cylindrical tank made of metal and having the transformer laminations and core in the oil filled tank. A high voltage input lead 137 is connected through the lid 135 to the transformer windings and the low voltage output is taken from lead 139. The brackets 133 mount the tank on a pole or support. A heat dissipating module 100A, in accordance with the invention, is affixed to tank 131 as will now be described with added specific reference to FIGS. 34 and 35.

FIG. 34 shows a heat dissipating module 100A in accordance with the invention including a rectangular arcuate shaped heat collection plate 108A adapted to conform to the periphery of the transformer tank 131 and is preferably formed of steel or aluminum. A heat dissipating fin 112A extends outwardly from plate 108A. A pair of metal straps 140A are positioned around the heat collection plate 108A to secure the plate firmly around the transformer tank 131 to transfer heat thereto. Note, the position bubble pump tube 105B indicated in FIG. 34 and illustrated in more detail in FIG. 35.

FIG. 35 is a cross section view of the drawing of FIG. 33. The heat dissipating module of the invention is indicated as 100A and includes the bubble generating chamber 106A, pump 105B, slurry flow paths 122, manifold 120A in fin 112A, and the slurry return flow tube 119A. FIG. 35 also shows clearance slots 141 for accepting the straps 140 (FIG. 34) for securing the heat collection plate 108A of module 100A on the side of tank 131. Suitable weather seal 153 protects against moisture. The operation of module 100A is substantially identical to that previously explained for module 100. More than one module 100A with a respective heat collection plate 108A can be mounted on the tank 131 with and each module being independent of one another and each module operating independently of the other modules. However the heat dissipation provided by the various modules 100A and the associated dissipating fins 112A to the tank 131 is cumulative. The number of modules 100A (and plates and fins) affixed to a tank 131 can be tailored to the heat dissipation requirements.

The heat transfer bridge module 100A provides numerous advantages and features. The 100A bridge is retrofittable to most isolation transformers. No changes have to be made to the mounting pole/support, nor to the transformer, nor to the electrical connectors. The 100A bridge will not interfere with existing maintenance or power resetting procedure. The 100A automatically creates uniform bubble and flow generation in response to heat developed in the transformer tank 131 and requires no other input power. Importantly, the metallic slurry 99 provides five to seven times the thermal transport rate of fluid alone. Many other advantages and features could be enumerated.

FIG. 36 shows a transformer tank 131A externally similar to transformer tank 131A but having two similar oil cooling tubes 141 and 143 extending outwardly from the tank side. The two tubes are positioned diametrically opposite one another. Each is essentially a closed loop with the open ends of the loop exiting and then returning to the tank interior.

FIG. 37 is a cross section of the tank of FIG. 37 specifically to show the fluid flow structure of the tank 131A. The fluid or slurry 99 flow paths through the two separate cooling tubes are independent of each other but are essentially the same. A description of the structure associated with tube 143 applies to tube 141. Note that the heat source in tank 131 A comprises the electrical winding 157 and the laminations 155 which produce heat and convey the heat energy through the oil 139 in the tank effective to pump tube 105C. The pump tube 105C itself functions as a chamber for generating bubbles. Suitable inductance shield 149A is mounted between the electrical windings and the tube 105C. Also, an insulation sleeve 149 is mounted on pump tube 105C. A portion 149A of the insulation shield is movable (slidable) on pump tube 105C to be moved or positioned as needed to accommodate hot spots. When the electrical windings 157 and lamination 155 become hot, the bubbles are formed in pump tube 105C adjacent the winding 157. The bubble formation is indicated in the pump tube sections 154 and 156 of tube 105C. The action and function of the bubbles 116 and slurry 99 is identical to that previously described. The difference in the embodiment of FIGS. 36 and 37 is that the pump tube 105C couples directly into the oil filled cooling tube 117A. That is, the tube 122A carrying the slurry is immersed in the oil of cooling tube 143. Minimal external structure is needed on the exterior of transformer tank 131A.

FIG. 38 shows a variation of the positioning of the heat transfer module 100D wherein the pump tube 105E is mounted in a recess 164 formed in the transformer laminations 161. The operation of the generation of bubbles and the circulation of the slurry 99 (see FIG. 39) is as has been previously described. In this embodiment the pump tube 105E functions as a direct metal to metal collector of heat by abutting the metal laminations 161. The flow return tube 119 provides a direct metal to metal contact with the heat dissipating fin 112E. As can be appreciated, the direct metal to metal contact provides an efficient heat transfer bridge.

FIG. 39 is a cross section view of the module 100C of FIG. 38 depict the metal slurry 99 driven by the bubbles 168 in a complete loop. A turbulence generating tube previously described with reference to FIGS. 32A and 32B is positioned in return tube 163. The return tube 163 connects to fin 162 to provide the efficient heat transfer.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. 

1. A heat dissipation assembly for electronic and electrical components utilizing a liquid cycling heat transfer pump comprising: a) an elongated container; b) a metal slurry fluid having a selectable boiling point contained in said container; c) heat sink means thermally coupled to a first section of said container; d) thermally coupling said heat source to provide heat energy to said fluid for generating in a second section of said container spaced fluid bubbles with hot fluid between said bubbles; e) mounting said container to enable said bubbles to rise up said container; f) said rising bubbles moving said fluid between the bubbles in the direction of the rising bubbles and toward said second section of said container wherein said heat sink means are positioned; and h) said heat sink means removing heat energy from said fluid.
 2. A heat dissipation assembly for electronic and electrical components as in claim 1 including, a) a closed tubular loop; b) a fluid having a low boiling point contained in said tubular loop and flowable through said loop; c) heat sink means thermally coupled to first sections of said loop; d) thermally coupling said heat source to provide heat energy to said fluid for generating spaced fluid bubbles in a section of said tubular loop; e) mounting said second section of said loop to enable said bubbles to rise up said second section of said tubular loop; f) conforming the dimensions of said second section and the dimensions of said bubbles section to confine hot liquid in said spaces between rising bubbles; g) said rising bubbles pushing and pumping said hot fluid through said second section of said loop toward said first section of said loop wherein said heat sink means are mounted; and h) said heat sink means removing heat energy from said hot fluid.
 3. A heat dissipation assembly for electronic and electrical components as in claim 1 including: a) a housing having heat concentrators for said assembly; b) fluid retaining tubes within said assembly; c) a fluid slurry comprising a fluid having a low boiling point and micro metallic particles contained within said assembly; d) fluid pathways formed in said assembly; e) means for mounting said housing adjacent a heat source; f) said fluid forming bubbles when heated above said boiling point; g) positioning at least one of said fluid pathways to direct said bubbles to move upwardly away from said heat source; h) said bubbles pushing said slurry toward at least one heat concentrator to remove heat from said slurry; and i) fluid return pathways for cycling said cooled slurry back toward said heat source.
 4. A heat dissipation assembly for electronic and electrical components as in claim 1 comprising a) multiple heat transfer pumps; b) means for mounting said pumps adjacent sources of heat; c) each pump utilizing a liquid having a low boiling point and forming bubbles when heated above said boiling point; d) each pump including multiple liquid flow paths; e) said bubbles providing a force to push said liquid through said flow paths; f) heat concentrators mounted adjacent said liquid flow paths for removing heat energy from said liquid.
 5. A heat transfer bridge for providing cooling to a transformer tank, said bridge comprising a) an enclosed container; b) a slurry comprising formed of fluid having a low boiling point and metallic foam particles contained in said container; c) heat sink fins; d) tube means for circulating said slurry adjacent at least a portion of said transformer tank to absorb heat energy from said tank; e) a bubble generating chamber for developing bubbles in said slurry as a result of heat absorbed by said slurry from said tank; f) said bubbles creating a pressure force for moving and stirring said fluid to circulate through tube means; and h) said heat sink means removing heat energy from said fluid whereby said tank is cooled.
 6. A heat dissipation assembly for electronic and electrical components as in claim 1 further including, a) an enclosed container for cooling a hot component or other hot spot on a circuit board, b) a fluid having a selectable boiling point contained in said container; c) heat sink means thermally coupled to a first section of said container; d) inserting at least a portion of said heat source in said fluid to provide heat energy to said fluid for generating, in a second section of said container, spaced fluid bubbles; e) mounting said container to enable said bubbles to move in said container; f) said bubbles creating a pressure force for moving and stirring said fluid to circulate toward said second section of said container wherein said heat sink means are positioned; and h) said heat sink means removing heat energy from said fluid.
 7. A cooling container as in claim 6 further including, a) a fluid having a selectable boiling point contained in said container; b) heat sink means thermally coupled to a first section of said container; c) thermally coupling said heat source to provide heat energy to said fluid for generating in a second section of said container spaced fluid bubbles with hot fluid between said bubbles; e) mounting said container to enable said bubbles to rise up said container; f) said rising bubbles moving said fluid between the bubbles in the direction of the rising bubbles and toward said second section of said container wherein said heat sink means are positioned; and h) said heat sink means removing heat energy from said fluid.
 8. A heat dissipation assembly for electronic and electrical components as in claim 1 including, a) a closed tubular loop; b) a fluid having a low boiling point contained in said tubular loop and flowable through said loop; c) heat sink means thermally coupled to first sections of said loop; d) thermally coupling said heat source to provide heat energy to said fluid for generating spaced fluid bubbles in a section of said tubular loop; e) mounting said second section of said loop to enable said bubbles to rise up said second section of said tubular loop; f) conforming the dimensions of said second section and the dimensions of said bubbles section to confine hot liquid in said spaces between rising bubbles; g) said rising bubbles pushing and pumping said hot fluid through said second section of said loop toward said first section of said loop wherein said heat sink means are mounted; and h) said heat sink means removing heat energy from said hot fluid.
 9. A heat dissipation assembly for electronic and electrical components as in claim 1 further comprising, a) a housing including heat concentrators for said assembly; b) fluid retaining tubes within said assembly; c) a fluid having a low boiling point contained within said assembly; d) said tubes forming fluid pathways; e) means for mounting said housing adjacent a heat source; f) said fluid forming bubbles when heated above said boiling point; g) positioning at least one of said tubes pathways to direct said bubbles to move upwardly away from said heat source; h) said bubbles pushing said fluid toward at least one heat concentrator to remove heat from said; and i) fluid return pathways for cycling said cooled fluid chloride back toward said heat source; and j) repeating the cycle.
 10. A heat dissipation assembly as in claim 9 wherein the boiling point of said fluid is below the temperature at which electronic and electrical components may be degraded. 